1. Field of the Invention
The present invention relates to a semiconductor device and a semiconductor device manufacturing method, and more particularly, to a semiconductor device which comprises inductors, and a method of manufacturing the same.
2. Description of Related Art
For operating a plurality of logic chips in tandem with one another, it is necessary to synchronize operations of the plurality of logic chips with one another to smoothly transmit/receive signals among the plurality of logic chips.
For synchronizing operations of respective logic chips with one another and transmitting/receiving signals among logic chips under a circumstance where the respective logic chips operate with different supply voltages, a non-contact type signal transmission/reception scheme using capacitors or inductors is desirable in order to avoid problems associated with the transmission/reception of signals caused by the difference in supply voltage. In particular, the non-contact type signal transmission/reception scheme is useful for a semiconductor device which comprises stacked logic chips, in order to accomplish high-density mounting of logic chips.
In this type of conventional semiconductor device, a plurality of semiconductor integrated circuit chips each formed with a plane inductor are stacked one on another, as shown in FIGS. 1, 7, 9, and 11 of JP2005-203657A, and information is communicated among the semiconductor integrated circuit chips, making use of electromagnetic coupling among the plane inductors.
In the semiconductor device described in JP2005-203657A, a semiconductor integrated circuit chip (substrate) intervenes between two plane inductors which are involved in the communication of information. Therefore, the two plane inductors are required to have a coil area (coil diameter) proportionate to the thickness of the semiconductor integrated circuit chip (substrate) in order to electromagnetically couple the two plane inductors.
Accordingly, since a semiconductor integrated circuit chip (substrate) has a larger thickness, a plane inductor should have a larger coil area and occupy a larger proportion of a circuit integration area on the semiconductor integrated circuit chip (substrate). Consequently, the degree of freedom in designing a circuit will be limited on the semiconductor integrated circuit chip.